However, full mineralization of complex chemicals such as pharmaceutical residues by AOPs is not cost-effective, and therefore partial degradation to more biodegradable or less toxic intermediates is the key.

To unravel degradation pathways and to quantify micropollutant residues, attention is given to mass transfer mechanisms, degradation kinetics and process optimization.

Advanced oxidation processes, based on the production of highly oxidative and non-selective hydroxyl radicals, have the potential to upgrade conventional biological waste water treatment plants that were initially not designed to efficiently remove hazardous organic micro-pollutants.